TABLE 1.
Characteristics of included studies
| Reference | LBP type, duration. | Total N in placebo and control groups, mean age (SD) and percentages females | Study design | Outcome measurement | Placebo group | Control group | Protocol | Results |
|---|---|---|---|---|---|---|---|---|
| Bialosky et al., (2014) | Not specified, Duration: 16 weeks |
N = 72, Age: 31.68 (11.85) Females (%) : 64% |
RCT | 0 (baseline) and 2 weeks (postintervention) | Sham manipulative therapy and enhanced sham by instructions | No‐treatment: sit down and wait. | 5 therapy sessions in 2 weeks, each lasting 5 min. |
Clinical pain (intensity): Baseline: NRS placebo; 43.78 (22.45)/NRS control; 33.93 (26.21) Within groups: NRS placebo; 29.88 (20.64), DS: 14.04 (3.51)/NRS control; 25.73 (22.04), DS: 8.20 (2.39) Between (all) groups: p =.68, ES (η2) = 0.02 Disability: Baseline: ODI placebo; 14.22 (8.56)/ODI control; 20.04 (15.27) Within groups: ODI placebo: 12.23 (10.22), DS: 2.08 (1.44)/ODI control: 17.50 (12.66), DS: 2.53 (1.60) Between (all) groups: p =.73, ES (η2) = 0.01 |
| Borges et al. (2013) | CLBP, Duration: 4.4 years |
N = 29 Age: 39.6 (9.6) Females (%) : 77% |
RCT | 0 (baseline), 3 and 6 weeks (postintervention) | Sham laser application on acupressure points | No‐intervention | 12 therapy sessions in 6 weeks, each lasting 20 min. |
Clinical pain (intensity): Baseline: NRS placebo; 5.7 (1.0)/NRS control: 5.0 (1.2) Within groups: NRS placebo; 4.8 (1.5)–4.7 (1.0), p >.05, ES(d) = 17% /NRS control; 5.3 (1.0)–5.9 (1.2), p >.05, ES(d) = −17% Between groups a : Z = 1.06, p =.29, ES(smd) = 0.38 Disability: not assessed |
| Brinkhaus et al., (2006) | CLBP, Duration: 14.7 (11.1) years |
N = 144 Age: 58.8 (9.1) Females (%) : 68% |
RCT | 0 (baseline), and 8 weeks. | Minimal acupuncture with needling of nonspecific areas. | Waiting list group could use NSAIDs as back up medication | 12 sessions of 30 min in 8 weeks; in the first 4 weeks twice a week, than weekly for remaining 4 weeks. |
Clinical pain (intensity): Baseline: NRS placebo; 66.6 (15.7)/NRS control; 66.1 (13.6) Within groups: NRS placebo; 43.7 (29.8), DS 23.6 (31.0)/NRS control; 58.6 (25.1), DS 6.9 (22.0) Between groups a : Z = 3.18, p =.001, ES(smd) = 0.54 Disability: Baseline: PDI placebo; 31.5 (11.1)/PDI control; 31.0 (13.3) Within groups: PDI placebo; 21.5 (13.2)/PDI control; 27.1 (14.1). Between groups a : Z = 4.02, p <.001, ES(smd) = 0.69 |
| Bush et al., (1985) | CLBP, Duration: 10–13 years |
N = 48, Age: 20–65 yrs. Females (%): 47% |
RCT | 0 (baseline), postintervention and 3 months (follow‐up) | Stabilization of back with temperature feedback | Waiting list group | At least 8 intervention sessions, each lasting 40 min. + exercises at home 4/day. |
Clinical pain (intensity): Baseline: NRS placebo; 3.37/NRS control; 3.32 Within groups: not shown Between (all) groups: MANOVA for DLBP and MGPQ was not significant Disability: not assessed |
| Carvalho et al., (2016) | CLBP, Duration: not reported |
N = 76, Age: Placebo: 44.4 (13.2) Control: 44.1 (13.7) Females (%) : 71% |
RCT | 0 (baseline), and 3 weeks. | Open label placebo where participants are informed that they will receive an inert substance. | Usual care, after 3 weeks of testing participants could still use placebo pills if they wanted to. | Placebo pills twice a day for 3 weeks. |
Clinical pain (intensity): Baseline: NRS placebo; 4.8 (1.8)/NRS control; 5.0 (1.7) Within groups: NRS placebo; DS 1.48 (1.79)/NRS control; DS 0.44 (2.13) Between groups: F = 11.02, p <.001, ES(g) = 0.76 Clinical pain (bothersomeness): Baseline: NRS placebo; 6.0 (2.1)/NRS control; 5.6 (2.3) Within groups: NRS placebo; 1.44 (2.46)/NRS control; 0.78 (2.61) Between groups: F = 1.71; p =.195 ES(g) = 0.21 Disability: Baseline: RMDQ placebo; 8.5 (4.6), RMDQ control; 9.9 (5.2) Within groups: RMDQ placebo; DS 2.86 (3.91)/RMDQ control; DS 0.02 (3.73) Between groups: F = 12.10, p <.001, ES(g) = 0.74 |
| Charron et al., (2006) | CLPB, Duration: 8.4 (6.9) years |
N = 16, Age: 39.8 (13.2) Females (%): 37.5% |
Cross‐over study, pseudo random. | 0 (baseline) and postintervention | Injection of 1ml saline with a specific instruction | Injection of 1ml saline with a control instruction | Two sessions on different days, lasting for 3 hr, receiving both placebo or control on different days. |
Clinical pain (intensity): Baseline: not reported Within groups: MANOVA placebo; p =.08/MANOVA control; p >.05. Between groups: p =.142 Clinical pain(unpleasantness): Baseline: not reported Within groups: MANOVA placebo; p =.038/MANOVA control; p >.05 Between groups: p =.046 Disability: not assessed |
| Cherkin et al., (2009) | CLBP, Duration: ≥3 months |
N = 363 Age: 47 (13) Females (%): 62% |
RCT | 0 (baseline), 8, 26 and 52 weeks. | Simulated acupuncture with a toothpick and specific instructions, no skin penetration. | Usual care consisting of primary care, pain medications and physiotherapy visits. | 10 treatment sessions lasting 20 min in 7 weeks, in the first 3 weeks twice a week, than weekly for remaining 4 weeks. |
Clinical pain (bothersomeness): Baseline: NRS placebo; 4.9 (2.3)/NRS control; 5.4 (2.3) Within groups: NRS Placebo; 3.0 (2.4), 3.5 (2.7), 3.4 (2.7)/NRS control; 4.7 (2.6), 4.4 (2.6), 4.1 (2.6) Between groups: (placebo >control) 8 weeks MD −1.56 (95% CI −2.11 to −1.02) p <.05 26 weeks MD −0.78 (95% CI −1.36 to −0.19) p <.05 52 weeks MD −0.62 (95% CI −1.21 to −0.03) p <.05 Disability: Baseline: RMDQ placebo; 9.8 (5.1)/RMDQ control; 11.0 (5.1) Within groups: RMDQ placebo; 5.4 (4.9), 6.4 (6.0), 6.2 (5.8)/RMDQ control; 8.9 (6.0), 8.4 (6.0), 7.9 (6.5) Between groups: (placebo >control) 8 weeks MD −2.91 (95% CI −3.96 to −1.86) p <.05 26 weeks MD −0.78 (95% CI −1.36 to −0.19) p <.05 52 weeks MD −0.98 (95% CI −2.11 to 0.14) p = NS |
| Degenhardt et al., (2014) | CLPB, Duration: 9.1 (6.3) years |
N = 20, Age: 36 (11) Females (%) : 73% |
RCT | 0 (baseline), 1 and 24 hr postintervention | Sham ultrasound | No‐intervention | A single session of 60 min, sham ultrasound lasted 20 min and afterwards 40 min resting. |
Clinical pain (intensity): Baseline b : NRS placebo; 4 (3;4)/NRS control; 4 (2;6) Within groups b : NRS placebo; 3(1:3), 2.5(2:3), Friedman: p =.01/NRS control; 3.5(2:6), 3.5(2:5), Friedman: p =.64 Between (all) groups: nonparametric testing at 1h and 24 hr; p =.37, p =.51 Disability: not assessed |
| Eardley et al., (2013) |
CLPB, Duration: (per group) SPKP: 11.6 (8.6) WLC: 9.2 (6.6) |
N = 46, Age: Sham PKP: 48.1 (10.6) Waiting list control: 44.6 (10.3) Females (%) : 60% |
RCT | 0 (baseline), after every week in first 5 weeks (pain), 5 weeks (postintervention) and 7 weeks (follow‐up). | Sham PKP with sham rechecks and without verbal advice | Waiting list group for 6 weeks, than randomized to sham or PKP | 5 therapy sessions in 5 weeks, each lasting 4–60 min. |
Clinical pain (intensity): Baseline: VAS placebo; 51.8 (19.2)/VAS control; 52.2 (20.5) Within groups: VAS placebo; 36.0 (19.8), DS −15.8(18.1)/VAS control; 57.7 (19.2), DS 3.8 (20.9). Between groups: MD −11.9 (95% CI −20.8; −23.0), p =.10 Disability: Baseline: RMDQ placebo; 11.3 (4.1)/RMDQ control; 10.4 (5.2) Within groups: RMDQ placebo; 4.9(4.5), DS −6.4(5.2)/RMDQ control; 10.1(5.2), DS 0.0(4.6). Between groups: MD −6.1 (95% CI −5.9; 0.1), p <.005, ES = 1.4 |
| Faas et al., (1993) | ALBP, Duration: ≤ 3 weeks |
N = 280, Age: 36 Females (%) : 43% |
RCT | 0 (baseline), 1 month, 3 months and 12 months (follow‐up) | Sham ultrasonography with lowest possible dose next to zero (0.1 watt/cm2) | Treatment as usual(painkillers and instructions) | 10 sessions in 5 weeks (twice a week) lasting 20 min. |
Clinical pain (intensity): Baseline: NRS placebo; 36.6/NRS control; 38.1 Within groups: NRS placebo; DS −19 (23), −22 (28), −26 (26)/NRS Control; DS −19 (21), −24 (24), −26 (23). Between groups a : Z = 0.00, p = 1.00, ES(smd) = 0.00 Disability: Baseline: NRS placebo; 23.3/NRS control; 24.3 Within groups: NRS placebo; DS −10 (18), −13 (19), −15 (19)/NRS Control; DS −9 (19), −12 (20), −14 (19). Between groups a : Z = 0.45, p =.65, ES(smd) = −0.05. |
| Ikemoto et al., (2020) | CLBP, Duration ≥3 months |
N = 52, Age: 66.8 (13.4) Open label placebo: 68.2 (13.0) Treatment as usual: 65.3 (13.8) Females (%): 68.2% |
RCT | 0 (baseline), week 3 (during intervention), and week 12 (post‐intervention) | Open label placebo where participants are informed that they will receive an inert substance. | Treatment as usual (education and painkillers) | Placebo pills twice a day for 12 weeks |
Clinical pain (intensity): Baseline: NRS placebo; 5.3 (1.9)/NRS control; 5.5 (1.6) Within groups: NRS placebo; DS −0.9 (1.8), −1.1 (1.9)/NRS control; −0.2 (1.8), −0.8 (1.9) Between groups: placebo >control at 3 weeks p =.19, d = 0.38/ at 12 weeks placebo >control F = 1.00, p =.37, η2 = 0.05 Disability: Baseline: RMDQ placebo; 9.9 (3.7)/RMDQ control; 10.3 (4.0) Within groups: RMDQ placebo; −2.2 (2.9)/RMDQ control; −1.4 (3.6) Between groups: at 3 weeks placebo >control; p =.40; d = 0.24 at 12 weeks placebo >control F = 0.82, p =.37, η2 = 0.02 |
| Kim et al., (2020) |
CLBP ≥6 months. Duration: (per group) SA: 10.6 years (10.8) ML: 6.0 years (5.4) TAU: 9.2 years (7.6) |
N = 60 Age: 41.2 (12.0) Sham acupuncture: 41.8 (12.2) Mock laser acupuncture: 41.7 (12.3) Treatment as usual: 39.1 (9.8) Females (%): 52% |
RCT | 0 (baseline) and during 4 weeks treatment period |
Sham acupuncture: acupoints were pressured with non‐penetrating Streitberger needles Mock laser acupuncture: laser was held over acupoints for 15 s. |
Treatment as usual (education +painkillers) | Six sham or mock acupuncture treatments over 4 weeks: twice per week in the first half and once per week in the second half. |
Clinical pain (bothersomeness): Baseline: not reported Within groups: not reported Between (all) groups: F = 0.26, p =.86 Disability: not assessed |
| Klinger et al., (2017) |
CLBP, Duration: (per group) OI: 119.33 (75.23) months OI +cond: 158.83 (138.96) months PI: 165.67 (117.17) months PI +cond: 162.17 (106.86) months |
N = 48, Age: 49.97 (13.64) Females (%): 75% |
RCT | 0 (baseline), before and after first exercise, before and after first solution (postintervention), before and after second exercise, before and after second solution (postintervention). | Opioid instruction (with or without conditioning) about an oral saline solution | Open placebo instruction (with or without conditioning) about an oral saline solution | One session of 2 hr during which 2 solutions were administered after exercises. Conditioning happened between the administration of solutions. |
Clinical pain(intensity): Baseline: VAS Placebo; 5.00 (2.09)/VAS Placebo +cond; 5.08(1.73)/VAS control; 4.67(1.67)/VAS control +cond; 5.25(1.87) Within groups: VAS Placebo; 4.00 (2.13), 3.00(2.73), p <.01, d = 0.83/VAS Placebo +cond; 3.58(1.56), 1.92(1.73), p <.01 d = 1.83/VAS control; 5.00(1.76), 5.58(1.78), p <.01, d = −0.64/VAS control +cond; 5.25(1.55), 4.58(2.31), p <.26, ES(d) = 0.32. Between groups: VAS placebo +cond > placebo; MD: −1.08 p: 1.00/VAS placebo +cond > control +cond; MD: −2.67 p: 0.03/VAS placebo +cond > control; MD: −3.92 p: 0.001/VAS placebo >control + cond; MD: −1.58 p: 0.52/VAS placebo >control; MD: −2.83 p: 0.018/VAS control +cond > control; MD: −1.25 p = 1.00 Disability: Baseline: FC placebo; 52.52(22.89)/FC placebo +cond; 60.56(20.78)/FC control; 51.11(15.13)/VAS control +cond; 50.00(20.99) Within groups: FC placebo; 67.78(29.24), p <.01, ES(d) = −0.59/FC placebo +cond; 77.22(15.43), p <.01, d = −0.92/FC control; 44.44(15.66), p =.06, ES(d) = 0.43/FC control +cond; 53.89(24.03), p =.22 ES(d) = −0.17 Between groups a : FC placebo +cond > FC control +cond; Z = 2.51, p =.01, ES(smd) = 1.12/FC Placebo >FC control; Z = 2.21, p =.02, ES(smd) = 0.97 |
| Leibing et al. (2002) | CLPB, Duration: 9.6 (8.2) years |
N = 91, Age: 48.1 (9.7) Females (%): 58% |
RCT | 0 (baseline), 12 weeks (postintervention) and 9 months (follow‐up) | Active physiotherapy for 12 weeks (26 sessions) followed by minimal acupuncture for 12 weeks(20 sessions) | Active physiotherapy for 12 weeks, during testing treatment with painkillers | 20 intervention sessions in 12 weeks, each lasting 20 min. |
Clinical pain (intensity): Baseline: VAS placebo; 5.3 (1.8)/VAS control; 5.4 (1.9) Within groups: VAS placebo; 3.2 (1.9)–3.4 (2.1), DS −2.1 (2.2), −1.8 (2.2)/NH; 4.4 (2.5)–4.5 (2.7), DS −1.0 (1.7), −0.9 (2.0) Between groups a : Z = 2.52, p =.01, ES(smd) = 0.54 Disability: Baseline: PDI placebo; 25.5 (10.4)/PDI control; 24.9 (13.7) Within groups: PDI placebo; 15.7 (10.1)–16.9 (11.6), DS −9.7 (10.5) −8.5 (11.3) /PDI control; 22.2 (15.4)–22.6 (15.8), DS −2.6 (7.8), −2.3 (10.0) Between groups a : Z = 2.32, p =.02, ES(smd) = 0.49 |
| Pires et al. (2020) |
CLBP ≥3 months, Duration: (per group) Placebo: 44.4 (52.6) months Control: 58.2 (76.2) months |
N = 42, Age: Placebo: 38.9 (10.3) Control: 45.3 (12.0) Females (%): 75% |
RCT | 0 (baseline), post‐intervention, and at 30 min (follow‐up). | Missner® surgical tape (5 cm in width) placed on the longissimus muscle. | No bandage | One session during which tape was applied after exercise intervention. |
Clinical pain (intensity): Baseline: NRS placebo; 7.2 (1.3)/NRS control; 7.0 (2.5) Within groups: NRS placebo; 6.0 (2.8)–5.0 (3.2)/NRS control; 5.0 (3.2)–5.0 (3.2) Between groups: Post‐intervention MD: 0.24 (95% CI −1.06; 1.54), p =.72 At 30 min MD: −0.52 (95% CI −1.83; 0.78) Disability: Baseline: RMDQ placebo; 13.2 (5.3)/RMDQ control; 12.5 (6.7) Within groups: not assessed Between groups: not assessed |
| Pach et al., (2011) | CLBP, Duration: 15 (12) years |
N = 87, Age: 57 (11) Females (%): 64% |
RCT | 0 (baseline), 8 and 26 weeks. | Placebo group received an injection with isotonic saline (rescue pain medication) | Rescue pain medication with peripherally acting analgesics | 12 treatment sessions in 8 weeks; twice per week in the first half, than once per week in the second half. |
Clinical pain (intensity): Baseline: VAS placebo; 62.5 (13.9)/VAS control; 59.0 (14.1) Within groups(mean and 95% CI): VAS placebo; 41.8 (30.1; 53.6), 35.5 (24.2; 46.9)/VAS control; 53.0 (41.8; 64.2), 45.0 (34.1; 55.9). Between groups a : Z = 1.42, p =.15, ES(smd) = 0.31 Disability: Baseline: PDI placebo; 29.0 (13.8)/PDI control; 27.7 (11.8), HFAQ placebo; 61.3 (21.8)/HFAQ control; 65.5 (17.4) Within groups(mean and 95% CI): PDI placebo; 24.1 (17.7–25.1), 25.9 (22.5; 29.3)/PDI control: 25.9 (22.5; 29.3), 22.7 (18.7; 26.7). HFAQ placebo; 68.4 (63.8; 73.0), 67.4 (61.0; 73.8)/HFAQ control; 64.8 (60.5; 69.1), 64.8 (58.8; 70.9). Between groups a : Z = 1.54, p =.12, ES(smd) = 0.33 |
| Sanders et al., (1990) | ALBP, Duration: <2 weeks |
N = 12, Age: Males: 41 (30.9) Females 33 (8.6) Females (%): 50% |
RCT | 0 (baseline), 5 and 30 min (postintervention) | Sham manipulation | No intervention | A single intervention, duration not specified. |
Clinical pain (intensity): Baseline: not reported Within groups: not reported Between groups: no significant difference. Disability: not assessed |
| Vas et al., (2012) |
ALBP, Duration: (per group) Sham: 5.0 (3.6) days Placebo: 6.5 (4.1) days Control: 6.8 (3.9) days |
N = 207, Age: Sham: 44.0 (9.4) Placebo: 43.6 (12.2) Control: 41.2 (12.0) Females (%): 58% |
RCT | 0 (baseline), 3, 12 and 48 weeks (follow‐up). | Sham acupuncture: needling nonspecific points, Placebo acupuncture: temporarily applied pressure with a blunt needle. | Conventional Therapy (painkillers and instructions) | 5 sessions in 2 weeks lasting 20 min. |
Clinical pain (intensity): Baseline: VAS sham; 71.5 (18.3)/VAS placebo; 68.3 (19.5)/VAS control; 69.5 (18.0) Within groups: not reported Between groups: not reported Disability: Baseline: RMDQ Sham; 12.6 (6.3)/RMDQ Placebo; 14.1 (5.2)/RMDQ control 12.4 (5.1) Within groups: RMDQ sham; DS 65.0 (40.5), 84.7 (28.9), 75.6 (37.4)/RMDQ placebo; DS 43.1 (58.9), 76.3 (41.5), 70.7 (55.4)/RMDQ control; DS 26.6 (58.9), 83.0 (23.2), 63.3 (57.4). Between groups a : Z = 3.79, p <.001, ES(smd) = 0.75 |
Abbreviations: ALBP, acute low back pain; CLBP, chronic low back pain; DLBP, Daily Low Back Pain Scale; DS, Difference Score; HFAQ, Hannover Functional Ability Questionnaire; MGPQ, McGill Pain Questionnaire; ML, Mock Laser Acupuncture; NRS, Numeric Rating; NSAID, NonSteroidal Anti‐Inflammatory Drugs; OI, Opioid Instruction; PDI, Pain Disability Index; PI, Placebo Instruction; PKP, Professional Kinesiology Practice; RCT, Randomized Controlled Trial; RMDQ, Roland Morris Disability Questionnaire; SA, Sham Acupuncture; SPKP, Sham Professional Kinesiology Practice; TAU, Treatment As Usual; WLC, Waiting List Control.
Between group analyses are conducted by the reviewers.
Numbers are reported as median and interquartile ranges.